2012 250 sx detonating

[El Liebre]

Oh wow 60:1...

The 50:1 ratio I was refering to was the one recommened by the Amsoil Dominator oil.

But yeah I would feel iffy about running that little amount of oil into a brand new bike too! Well any bike really...

[kx137]

I couldn't bring myself to doing 60:1 so I went with 50:1 as others recommended. Yeah I live in ft.worth - probably going to hit up that buffalo creek free ride day friday, maybe rivervalley again tommorrow - if open. I drive the white sprinter stop bye if you see me! Brian-

[VETMX808]

Yep, 50:1. No way would I ever run 60:1 as the manual suggests.

[mxboy2661]

im runnin 40-1 50-50 pump n cam2

[rpt50]

+1 on the chart in the manual. I have found that it is really close on my 09 sx. I jet for winter temps at my elevation. It's a tad rich in the summer, but not enough to bother re-jetting.

[SAthump]

I have a 160 mj, 42 pilot, ne1h, 4 position, 1 1/2 air screw, Interested to hear about your results as soon as possible. Thanks

I've only done a few heat cycles and quick ride on some trail around my house but so far have settled with [ 42p, NE!H 4th, 165m, as 1 1/2 out ] I'm running C12 with K2 40:1, oval bored carb, runs very crisp but may consider bumping the main up. I'll wait till a trip to the track to decide.

[Dingateer]

if anyone still cares about following this thread i will update. I've already got over 30 hours on my bike so it's definitely broken in. I posted my jetting specs during the winter and now it's warming up so i will change it again. It runs a little rich when it's hot outside so i left the 160 main where it was and put everything else back to stock. now it runs like a champ!

[JoeMcLaughlin]

You could run a thicker base gasket to lower the compression, that should solve your issue. How do you know you have deto? Are you hearing a ping or are you seeing deto pits on the piston dome? Do you know what compression your running? You may want to baseline things: find your compression, what base gasket you running, what is your squish. Is this a mod engine?

Joe............

[Dingateer]

it's all stock. i heard the ping when the engine was under heavy load, like riding in sand for example. i got it figured out and it runs really crisp